Op-art architecture designed for happiness.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

An ancient Egyptian temple in the middle of Madrid, Spain.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The marble facade hides a little-known medical museum with early surgical instruments and rare copies of canonical texts.

Two stone columns flank the grand Venice square, but there were supposed to be three.

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

Go inside to really appreciate this 500-year-old technological masterpiece.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

The yawning maw of this pagan visage is said to bite off the hands of liars.

A dead saint, a deadly poison, and a mysterious holy ooze.

Southern Italy's spinning top village.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

Erotic art covers the walls of the largest ancient pleasure palace.